Connexin 40 promoter-based enrichment of embryonic stem cell-derived cardiovascular progenitor cells

Background: Pluripotent embryonic stem (ES) cells that can differentiate into functional cardiomyocytes as well as vascular cells in cell culture may open the door to cardiovascular cell transplantation. However, the percentage of ES cells in embryoid bodies (EBs) which spontaneously undergo cardiovascular differentiation is low (< 10%), making strategies for their specific labeling and purification indispensable. Methods: The human connexin 40 (Cx40) promoter was isolated and cloned in the vector pEGFP. The specificity of the construct was initially assessed in Xenopus embryos injected with Cx40-EGFP plasmid DNA. Stable Cx40-EGFP ES cell clones were differentiated and fluorescent cells were enriched manually as well as via fluorescence-activated cell sorting. Characterization of these cells was performed with respect to spontaneous beating as well as via RT-PCRs and immunofluorescent stainings. Results: Cx40-EGFP reporter plasmid injection led to EGFP fluorescence specifically in the abdominal aorta of frog tadpoles. After crude manual enrichment of highly Cx40-EGFP- positive EBs, the appearance of cardiac and vascular structures was increased approximately 3-fold. Immuno fluorescent stainings showed EGFP expression exclusively in vascular-like structures simultaneously expressing von Willebrand factor and in formerly beating areas expressing alpha-actinin. Cx40-EGFP-expressing EBs revealed significantly higher numbers of beating cardiomyocytes and vascular-like structures. Semiquantitative RT-PCRs confirmed an enhanced cardiovascular differentiation as shown for the cardiac markers Nkx2.5 and MLC2v, as well as the endothelial marker vascular endothelial cadherin. Conclusions: Our work shows the feasibility of specific labeling and purification of cardiovascular progenitor cells from differentiating EBs based on the Cx40 promoter. We provide proof of principle that the deleted CD4 (Delta CD4) surface marker-based method for magnetic cell sorting developed by our group will be ideally suitable for transference to this promoter. Copyright (c) 2008 S. Karger AG, Basel

Posttraumatic Stress and Parenting Behaviors: The Mediating Role of Emotion Regulation

Maternal trauma has been linked with problematic parenting, including both harsh and permissive behaviors. However, little is known about mechanisms accounting for this association. The current study examined the potential impact of posttraumatic stress disorder (PTSD) and emotion regulation on dysfunctional parenting behaviors in a sample of community mothers. We hypothesized a mediation model wherein PTSD would be associated with dysfunctional parenting (i.e., lax and overreactive behaviors) indirectly through deficits in maternal emotion regulation. Seventy-eight community mothers of 18- to 36-month-old children were administered the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) and 19 mothers met criteria for PTSD. Mothers also completed self-report measures of difficulties with emotion regulation and maternal laxness and overreactivity in parenting. Results revealed that emotion dysregulation fully mediated relations between PTSD status and lax (but not overreactive) parenting behaviors. Compared to mothers without PTSD, those with PTSD reported greater lax parenting behaviors indirectly through greater emotion dysregulation. Mothers with PTSD may struggle to parent assertively when trauma symptoms interfere with emotion regulation abilities. The current study highlights the need to design interventions focused on helping trauma-exposed mothers manage distress, ultimately aiming to enhance parenting effectiveness and improve child outcomes

Variability in Growth and Age Structure Among Populations of Ribbed Mussels, Geukensia demissa (Dillwyn) (Bivalvia: Mytilidae), in Jamacia Bay, New York (Gateway NRA)

Growth rates, body weight, density and biomass of ribbed mussels, Geukensia demissa (Dillwyn), were determined at Spartina alterniflora marsh-flat sites in Jamaica Bay, New York (Lower Hudson Estuary). Cumulative growth and annual growth increments varied but rates were lower at sites within the central bay relative to peripheral sites. Local variability both in size at Ring-1 and size-specific annual growth rates probably account for the variability in cumulative length. No pattersn were noted in frequency distributions of shell size but congruence in age structure was observed among neighboring sites in some areas of the bay. Mussel densities were greater within Jamaica Bay than at most other locations reported in the literature and estimated biomass values were lower. Growth rates of Jamaica Bay mussels were lower than other populations in the northeastern American coast. Four hypotheses that may account for observed Geukensia growth rates in Jamaica Bay are presented and discussed: higher population density, higher vertical marsh levels, variability in phtyoplankton quality and/or quantity, long-term sublethal chemical pollution

Novel Roles for Selected Genes in Meiotic DNA Processing

High-throughput studies of the 6,200 genes of Saccharomyces cerevisiae have provided valuable data resources. However, these resources require a return to experimental analysis to test predictions. An in-silico screen, mining existing interaction, expression, localization, and phenotype datasets was developed with the aim of selecting minimally characterized genes involved in meiotic DNA processing. Based on our selection procedure, 81 deletion mutants were constructed and tested for phenotypic abnormalities. Eleven (13.6%) genes were identified to have novel roles in meiotic DNA processes including DNA replication, recombination, and chromosome segregation. In particular, this analysis showed that Def1, a protein that facilitates ubiquitination of RNA polymerase II as a response to DNA damage, is required for efficient synapsis between homologues and normal levels of crossover recombination during meiosis. These characteristics are shared by a group of proteins required for Zip1 loading (ZMM proteins). Additionally, Soh1/Med31, a subunit of the RNA pol II mediator complex, Bre5, a ubiquitin protease cofactor and an uncharacterized protein, Rmr1/Ygl250w, are required for normal levels of gene conversion events during meiosis. We show how existing datasets may be used to define gene sets enriched for specific roles and how these can be evaluated by experimental analysis

Glassy behaviour in an exactly solved spin system with a ferromagnetic transition

We show that applying simple dynamical rules to Baxter's eight-vertex model leads to a system which resembles a glass-forming liquid. There are analogies with liquid, supercooled liquid, glassy and crystalline states. The disordered phases exhibit strong dynamical heterogeneity at low temperatures, which may be described in terms of an emergent mobility field. Their dynamics are well-described by a simple model with trivial thermodynamics, but an emergent kinetic constraint. We show that the (second order) thermodynamic transition to the ordered phase may be interpreted in terms of confinement of the excitations in the mobility field. We also describe the aging of disordered states towards the ordered phase, in terms of simple rate equations.Comment: 11 page

Two-electron atoms, ions and molecules

The quantum mechanics of two-electron systems is reviewed, starting with the ground state of the helium atom and helium-like ions, with central charge $Z\ge 2$. For Z=1, demonstrating the stability of the negative hydrogen ion, H$^-$, cannot be achieved using a mere product of individual electron wave functions, and requires instead an explicit account for the anticorrelation among the two electrons. The wave function proposed by Chandrasekhar is revisited, where the permutation symmetry is first broken and then restored by a counter-term. More delicate problems can be studied using the same strategy: the stability of hydrogen-like ions $(M^+,m^-,m^-)$ for any value of the proton-to-electron mass ratio $M/m$; the energy of the lowest spin-triplet state of helium and helium-like ions; the stability of the doubly-excited hydrogen ion with unnatural parity. The positronium molecule $(e^+,e^+,e^-,e^-)$, which has been predicted years ago and discovered recently, can also be shown to be stable against spontaneous dissociation, though the calculation is a little more involved. Emphasis is put on symmetry breaking which can either spoil or improve the stability of systems.Comment: 16 pages, 2 figure

The QUEST-La Silla AGN Variability Survey

We present the characterization and initial results from the QUEST-La Silla AGN variability survey. This is an effort to obtain well sampled optical light curves in extragalactic fields with unique multi-wavelength observations. We present photometry obtained from 2010 to 2012 in the XMM-COSMOS field, which was observed over 150 nights using the QUEST camera on the ESO-Schmidt telescope. The survey uses a broadband filter, the $Q$-band, similar to the union of the $g$ and the $r$ filters, achieving an intrinsic photometric dispersion of $0.05$ mag, and a systematic error of $0.05$ mag in the zero-point. Since some detectors of the camera show significant non-linearity, we use a linear correlation to fit the zero-points as a function of the instrumental magnitudes, thus obtaining a good correction to the non-linear behavior of these detectors. We obtain good photometry to an equivalent limiting magnitude of $r\sim 20.5$. Studying the optical variability of X-ray detected sources in the XMM-COSMOS field, we find that the survey is $\sim75-80$% complete to magnitudes $r\sim20$, and $\sim67$% complete to a magnitude $r\sim21$. The determination and parameterization of the structure function (${SF}_{norm}(\tau) = A \tau^{\gamma}$) of the variable sources shows that most BL AGN are characterized by $A > 0.1$ and $\gamma > 0.025$. It is further shown that variable NL AGN and GAL sources occupying the same parameter space in $A$ and $\gamma$ are very likely to correspond to obscured or low luminosity AGN. Our samples are, however, small, and we expect to revisit these results using larger samples with longer light curves obtained as part of our ongoing survey.Comment: Accepted for publication in Ap

Dynamical Masses for Low-Mass Pre-Main Sequence Stars: A Preliminary Physical Orbit for HD 98800 B

We report on Keck Interferometer observations of the double-lined binary (B) component of the quadruple pre-main sequence (PMS) system HD 98800. With these interferometric observations combined with astrometric measurements made by the Hubble Space Telescope Fine Guidance Sensors (FGS), and published radial velocity observations we have estimated preliminary visual and physical orbits of the HD 98800 B subsystem. Our orbit model calls for an inclination of 66.8 $\pm$ 3.2 deg, and allows us to infer the masses and luminosities of the individual components. In particular we find component masses of 0.699 $\pm$ 0.064 and 0.582 $\pm$ 0.051 M_{\sun} for the Ba (primary) and Bb (secondary) components respectively. Modeling of the component SEDs finds temperatures and luminosities in agreement with previous studies, and coupled with the component mass estimates allows for comparison with PMS models in the low-mass regime with few empirical constraints. Solar abundance models seem to under-predict the inferred component temperatures and luminosities, while assuming slightly sub-solar abundances bring the models and observations into better agreement. The present preliminary orbit does not yet place significant constraints on existing pre-main sequence stellar models, but prospects for additional observations improving the orbit model and component parameters are very good.Comment: 20 pages, 6 figures, ApJ in press; tables 2 and 3 to be included in ApJ versio

Beauty Is in the Eye of the Beer Holder: An Initial Investigation of the Effects of Alcohol, Attractiveness, Warmth, and Competence on the Objectifying Gaze in Men

Despite literature revealing the adverse consequences of objectifying gazes for women, little work has empirically examined origins of objectifying gazes by perceivers. Integrating alcohol myopia and objectification theories, we examined the effects of alcohol as well as perceived female attractiveness, warmth, and competence on objectifying gazes. Specifically, male undergraduates (n = 49) from a large U.S. Midwestern university were administered either an alcoholic or placebo beverage. After consumption, participants were asked to focus on the appearance or personality (counterbalanced) of pictured women who were previously rated as high, average, or low in attractiveness, warmth, and competence. Replicating previous work, appearance focus increased objectifying gazes as measured by decreased visual dwell time on women’s faces and increased dwell time on women’s bodies. Additionally, alcohol increased objectifying gazes. Whereas greater perceived attractiveness increased objectifying gazes, more perceived warmth and perceived competence decreased objectifying gazes. Furthermore, the effects of warmth and competence perceptions on objectifying gazes were moderated by alcohol condition; intoxicated participants objectified women low in warmth and competence to a greater extent than did sober participants. Implications for understanding men’s objectifying perceptions of women are addressed, shedding light on potential interventions for clinicians and policymakers to reduce alcohol-involved objectification and related sexual aggression